Pipe replacement system

ABSTRACT

Pipe replacement devices, and systems are shown. Devices and systems may include jointed cutters and floating cutters to navigate difficult pipe replacement conditions. Devices and systems may also include replacement pipe with pre-installed supply hoses, such as lubricant supply and/or pneumatic supply hoses. Methods of pipe replacement are also described, including splitting old pipe and pulling in new pipe behind the equipment as splitting progresses.

PRIORITY

This application is a continuation of U.S. patent application Ser. No.16/287,855, filed Feb. 27, 2019, which is a Divisional of U.S. patentapplication Ser. No. 15/859,120, filed Dec. 29, 2017, which is a isContinuation of U.S. patent application Ser. No. 14/679,384, filed Apr.6, 2015, which is a Continuation of U.S. patent application Ser. No.13/722,004, filed Dec. 20, 2012, which is a Non Provisional of andclaims the benefit of priority under 35 U.S.C. Section 119(e), to U.S.Provisional Patent Application Ser. No. 61/577,951, filed on Dec. 20,2011, which is hereby incorporated by reference herein in its entirety.

BACKGROUND

Trenchless pipe replacement is useful for replacement of pipes withoutthe need to excavate the length of the pipe to be replaced. An exampleof trenchless pipe replacement includes pulling a cutting blade with anexpander through the pipe to be replaced, and attaching a new pipebehind the cutting blade. The pipe to be replaced is split, and pushedinto the surrounding soil, and the new pipe, of equal or largerdiameter, is pulled into the new space within the split pipe. Splitterare commonly used for small diameter pipes, and for pipes of a materialthat lends itself to splitting. Another example of trenchless pipereplacement includes pipe bursting.

Gas lines are one example of pipes where splitting is useful in pipereplacement. An example includes high density polyethylene (HDPE) gaspipe. Large quantities of 2 inch diameter HDPE gas pipes are currentlyin need of replacement. 300 miles of gas pipe in a single city in needof replacement is not uncommon. Given the desirability of minimizingtrenches, it is also desirable to minimize the size of entry and exitpits for operating trenchless equipment. Cutting pipes in small entryand exit pits can be a challenge due to the small amount of availablespace to operate cutting tooling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a pipe replacement device according to an embodiment of theinvention.

FIG. 2A shows a pipe replacement device according to an embodiment ofthe invention.

FIG. 2B shows an anchor block from FIG. 2A according to an embodiment ofthe invention.

FIG. 3 shows a cross section of the pipe replacement device from FIG. 2Aaccording to an embodiment of the invention.

FIG. 4 shows a cutter according to an embodiment of the invention.

FIG. 5 shows a cross section of the cutter from FIG. 4, according to anembodiment of the invention.

FIG. 6 shows a blade from a pipe replacement device according to anembodiment of the invention.

FIG. 7A shows a replacement pipe according to an embodiment of theinvention.

FIG. 7B shows a supply device according to an embodiment of theinvention.

FIG. 8 shows a cross section of the supply device from FIG. 7, accordingto an embodiment of the invention.

FIG. 9 shows a flow diagram of a method according to an embodiment ofthe invention.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which is shown,by way of illustration, specific embodiments in which the invention maybe practiced. In the drawings, like numerals describe substantiallysimilar components throughout the several views. These embodiments aredescribed in sufficient detail to enable those skilled in the art topractice the invention. Other embodiments may be utilized andmechanical, structural, or logical changes, etc. may be made withoutdeparting from the scope of the present invention.

FIG. 1 shows a pipe replacement device 100 according to an embodiment ofthe invention. The pipe replacement device 100 includes an expander 112located at a front portion of a reciprocating hammer 110. A towing cable102 is also shown coupled to a front end 113 of the expander 112. In oneexample, a combination of pushing forces from behind, provided by thereciprocating hammer 110, and pulling forces provided by the towingcable 102 are used to split the pipe to be replaced, and to pull in anew pipe in a trenchless replacement operation. Although a conicalexpander 112 is shown, other expanders may include offset, nonconcentric expanders. The term towing cable 102 includes any of avariety of towing structures, such as wire rope, or other flexible linesof sufficient strength.

A cutter 114 is shown coupled to the front end 113 of the expander 112.In one example, the cutter 114 includes a jointed cutter that is allowedto pivot at the front end 113 of the expander 112. In one example, aball joint 111 is included between the cutter 114 and the expander 112to better navigate the pipe replacement device 100 through a pipe to bereplaced. One particularly useful example is in trenchless replacementof polymeric pipe, such as buried natural gas lines.

In selected operations, such as splitting some types of polymeric pipe,a jointed cutter is advantageous. For example, selected polymeric pipewas placed in the ground by unrolling the pipe off a spool and looselylaying the pipe in a trench. When the pipe is later covered with dirt, anumber of small curves may remain in the pipe as a result of shapememory from the spool which the pipe was unrolled from. These smallcurves can be difficult to navigate in a subsequent splitting operationof a trenchless replacement operation.

In one example, the ball joint 111 between the cutter 114 and theexpander 112 is held together by pressure, and aligned by the towingcable 102. This configuration also makes modular substitution ofcomponents of the pipe replacement device 100. For example, a secondcutter 116 is shown as an optional component for use with smallerdiameter pipe. In one example, the second cutter 116 includes a taperedportion 115 that bridges a taper dimension between the cutter blades 117and the starting diameter of the expander 112.

In one example, a floating cutter 120 is included in the pipereplacement device 100. FIG. 1 shows the floating cutter 120 in anembodiment that also includes a ball joint 111 and a cutter 114. Otherconfigurations may include only a ball joint 111 and a cutter 114, oronly a floating cutter 120.

The floating cutter 120 allows great flexibility to split and/or weakenthe pipe to be replaced ahead of the expander 112 and reciprocatinghammer 110. Because the floating cutter is only constrained by theflexible towing cable 102, the floating cutter 120 more easily navigatescurves in the pipe to be replaced, such as an uncoiled polymeric pipe asdescribed above. Further, the floating cutter 120 is not constrained atthe front of the expander 112 in the way that the cutter 114 isconstrained. Because the floating cutter 120 is not coupled to a balljoint, or other joint, the only constraint on the floating cutter 120 isits connection to the towing cable 102. One technical challenge withtrenchless replacement in curvy pipes is the length of the reciprocatinghammer 110 which tends to direct the expander in a straight line. Theaddition of the floating cutter 120 in front of the expander 112 andreciprocating hammer 110 overcomes this challenge.

FIG. 2A shows a pipe replacement device 200 similar to the pipereplacement device 100 of FIG. 1. The pipe replacement device 200includes an expander 212 coupled to a front end of a reciprocatinghammer 210. Similar to the pipe replacement device 100 of FIG. 1, acutter 216 is shown with a number of cutting blades 218 attached. Anopening 202 to accept a towing cable is shown that passes through thecutter 216, and into the expander 212.

A lateral insertion pocket 214 is shown coupled to the opening 202. Thelateral insertion pocket 214 is adapted to accept a removable anchorblock 220 illustrated in place in FIG. 2A, and separate from the pipereplacement device 200 in FIG. 2B. In operation, the towing cable isinserted through the opening 202 into the lateral insertion pocket 214and the towing cable is guided laterally outward from the expander 212.The removable anchor block 220 is then attached to the end of the towingcable. Once attached, the removable anchor block 220 is seated back intothe expander 212, where it fits within the lateral insertion pocket 214.

Due to high puling forces during a trenchless replacement operation, itcan be difficult to remove a cable from the pipe replacement device 200once the replacement is complete. Using configurations shown in thepresent disclosure, after a replacement operation, the removable anchorblock 220 can be removed from the lateral insertion pocket 214 anddisengaged from the cable with ease.

An attachment device 221 is shown within the removable anchor block 220.In one example, the attachment device 221 includes a tapered wedgetightener. In one example, the attachment device 221 is an activetapered wedge tightener, in contrast to a passive tapered wedgetightener that is tightened by pulling on the cable with friction tomove the wedge segments. An actuator, such as the threaded fitting 224is shown in FIG. 2B and FIG. 3. The threaded fitting 224 can betightened down to press against wedge segments 222 to tighten againstthe cable.

In one example, the lateral insertion pocket 214 is located within ataper region of the expander 212. In the example shown, the removableanchor block 220 includes a surface 225 that aligns with a taper of theexpander 212. In this configuration, expansion of the pipe to bereplaced is more consistent due to the surface 225, and debris issubstantially prevented from falling into the lateral insertion pocket214.

FIG. 3 shows a cross section of the pipe replacement device 200 fromFIG. 2A. In one example, illustrated in FIG. 3, a jack screw 226 isincluded. After a replacement operation, the jack screw 226 can beactuated to press against the removable anchor block 220 to drive it outof the lateral insertion pocket 214, if necessary.

FIG. 3 also shows additional detail of the cutter 216. Similar toexamples described above, the cutter 216 is coupled to the expander 212at a ball joint 211. As shown in the Figure, the ball joint 211 is heldtogether by pressure along a towing cable (not shown), and the cutter216 is removable/interchangeable by pulling the ball joint 211 apart.

FIG. 3 further shows a cutting blade 218 located in a pocket 219 of thecutter 216. The cutting blade 218 is removable for optional replacement,should the cutting blade become dull or damaged. FIG. 3 illustrates ahole 217 located opposite the cutting blade 218. In one example, thecutting blades 218 are attached within the pockets 219 using an adhesivesuch as epoxy. In practice, if a cutting blade is to be replaced, apunch or other small tool is inserted within one or more holes 217opposite the cutting blade 218. The bond between the cutting blade 218and the pocket 219 can then be broken by hammering or otherwise drivingthe cutting blade 218 out of the pocket 219 from the back side. Althoughone cutting blade 218 is shown, embodiments of cutters 216 includingmultiple cutting blades 218 are also within the scope of the invention.

FIG. 4 shows a floating cutter 400 similar to the floating cutter 120described above. The floating cutter 400 includes a body 402 having oneor more pockets 404 adapted to accept cutting blades such as cuttingblade 600 shown in FIG. 6. The cutting blade 600 includes an edgeportion 602, and a mating portion 604 to closely fit within the pockets404.

Also shown in FIG. 4 are a number of holes 406. In one example at leastone hole is associated with a pocket 404 for removal of a worn ordamages cutting blade 600 similar to the process described for cutter216 described above. In the example of FIG. 4, two holes 406 areassociated with each pocket 404 to more effectively drive a cuttingblade 600 out for replacement.

In one example, the cutting blades 600 are attached within the pockets404 using an adhesive such as epoxy. In practice, if a cutting blade isto be replaced, a punch or other small tool is inserted within one ormore holes 406 opposite the cutting blade 600. The bond between thecutting blade 600 and the pocket 404 can then be broken by hammering orotherwise driving the cutting blade 600 out of the pocket 404 from theback side.

FIG. 4 shows a first attachment device 410 and a second attachmentdevice 414 coupled to ends of the floating cutter 400. In one examplethe first attachment device 410 and the second attachment device 414both include tapered wedge couplers. FIG. 5 illustrates at least onetapered wedge segment 411 of the first attachment device 410, and atleast one tapered wedge segment 415 of the second attachment device 414.As shown in FIG. 5, in one example, the first attachment device 410 andthe second attachment device 414 are opposing in operational direction.Opposing attachment devices 410, 414 provide secure location of thefloating cutter 400 at a chosen location along a towing cable. As aresult of opposing attachment devices 410, 414, the floating cutter 400cannot be slid axially along the towing cable in either direction whenthe attachment devices 410, 414 are actuated. Also shown in FIG. 5 is afirst threaded fitting 412 to actuate the tapered wedge segment 411 ofthe first attachment device 410. Additionally, a second threaded fitting416 is shown to actuate the tapered wedge segment 415 of the secondattachment device 414.

As discussed above, splitting curved pipes such as polymeric natural gaslines can be problematic, and present a number of technical challenges.Curves in the pipe to be replaced cause increases in friction within thepipe and surrounding soil, and may require large pulling forces toadvance a pipe replacement device such as described in embodimentsabove. Features such as a reciprocating hammer, a towing cable, jointedcutters, and floating cutters all provide enhancements to moreeffectively split old pipe, and advance new pipe into place as pulledbehind the reciprocating hammer.

In selected embodiments, the reciprocating hammer is a pneumaticallydriven hammer, with a supply of compressed air being supplied from apneumatic supply hose located within the pipe to be replaced. Inselected embodiments, a lubricant is also supplied from a lubricantsupply hose routed alongside the pneumatic supply hose. FIG. 7A shows across section of a replacement pipe 750 including a pneumatic supplyhose 752 and a lubricant supply hose 754. In one example the replacementpipe 750 includes polyethylene pipe. Other flexible polymeric pipes mayalso be used.

As illustrated in FIG. 7A, in one example, both supply hoses 752, 754are located within the replacement pipe 750. In one example, thereplacement pipe 750 is stored, ready for a job site, with the pneumaticsupply hose 752 and lubricant supply hose 754 pre-installed within thereplacement pipe 750.

FIG. 7B shows a supply device 700 to hold an amount of replacement pipesuch as replacement pipe 750. The supply device 700 includes a reel 702and a frame 704 to hold the reel 702. In configurations where one ormore supply hoses such as pneumatic supply hose 752 or lubricant supplyhose 754 are pre-installed within the replacement pipe 750 a job site ismuch easier to navigate, and much less space in needed. The replacementpipe 750 does not need to be laid out to feed in hoses such as pneumaticsupply hose 752 or lubricant supply hose 754 on site. In one example, amotor 708 is located on the frame 704 of the supply device 700 to drivethe reel 702 as needed. In one example, the motor 708 includes ahydraulic motor. A hydraulic motor is useful because other equipmentlocated at the job site may also use hydraulic fluid for power. Forexample, a winch used to pull the towing cable may also use hydraulicdrive.

In one example, a guide 706 is coupled to the frame 704 to direct thereplacement pipe 750 from off of the reel 702 into an entry pit wherethe splitting and replacement operation begins. The guide 706 mayinclude one or more rollers 707 to lower friction as the replacementpipe 750 is moved off the reel 702.

FIG. 8 shows a cross section of the supply device 700 from FIG. 7B. Apneumatic supply line 712 and a lubricant supply line 722 are shownlocated within a hub 703 of the reel 702. A first pneumatic supplyfitting 714 is shown in a location adapted for connection to thepneumatic supply hose 752 within the replacement pipe 750. A secondpneumatic supply fitting 710 is shown in a location outside the hub 703,adapted for connection to a source of compressed air. A first lubricantsupply fitting 724 is shown in a location adapted for connection to thelubricant supply hose 754 within the replacement pipe 750. A secondlubricant supply fitting 720 is shown in a location outside the hub 703,adapted for connection to a source of lubricant. In one example, thelubricant includes a bentonite slurry, although other lubricants arealso within the scope of the invention.

Because the pneumatic supply line 712 and the lubricant supply line 722are located within the hub 703 of the reel 702, compressed air andlubricant can be delivered as needed, while replacement pipe is spooledoff the reel, to pipe replacement devices such as examples 100, 200described above.

FIG. 9 illustrates a flow diagram of an example method of trenchlesspipe replacement according to an embodiment of the invention. Operation902 recites driving an expander through a pipe using a reciprocatinghammer. Operation 904 recites pulling the reciprocating hammer throughthe pipe with a cable while concurrently driving the expander with thereciprocating hammer. Operation 906 recites splitting the pipe in frontof the expander using a floating cutter attached to the cable at alocation separate, and in front of the expander. Other example methodsfurther include splitting the pipe at a location adjacent to theexpander, such as with a jointed cutter. Other example methods furtherinclude supplying lubricant and compressed air while splitting, whereinthe lubricant and compressed air are supplied through supply linesstored within a replacement pipe. As described above, in one example,the replacement pipe is spooled off a reel, and the lubricant andcompressed air are provided through fittings in a hub of the reel.

Although a particularly useful example of splitting old curved polymericnatural gas lines is used as an example in selected descriptions above,the invention is not so limited. Other trenchless replacement operationswith other pipe materials such as copper, lead, or other metals are alsopossible.

While a number of advantages of embodiments of the invention aredescribed, any lists of above mentioned advantages are not intended tobe exhaustive. Although specific embodiments have been illustrated anddescribed herein, it will be appreciated by those of ordinary skill inthe art that any arrangement which is calculated to achieve the samepurpose may be substituted for the specific embodiment shown. Thisapplication is intended to cover any adaptations or variations of thepresent invention. It is to be understood that the above description isintended to be illustrative, and not restrictive. Combinations of theabove embodiments, and other embodiments will be apparent to those ofskill in the art upon reviewing the above description. The scope of theinvention includes any other applications in which the above structuresand methods are used. The scope of the invention should be determinedwith reference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

1. (canceled)
 2. A pipe replacement device, comprising: an expander; a lateral insertion opening in a front of the expander to accept a towing cable anchor; a reciprocating hammer coupled behind the expander; and a jointed cutter that abuts a front end of the expander.
 3. The pipe replacement device of claim 2, wherein the towing cable anchor is optionally removable from an end of the towing cable.
 4. The pipe replacement device of claim 3, wherein the towing cable anchor includes a tapered wedge tightener.
 5. The pipe replacement device of claim 4, wherein the tapered wedge tightener includes a threaded fitting to actuate tightening.
 6. The pipe replacement device of claim 2, further including a jack screw configured to assist removal of the towing cable anchor.
 7. The pipe replacement device of claim 2, further including a reciprocating hammer coupled behind the expander.
 8. A pipe replacement device, comprising: an expander; a lateral insertion opening in a front of the expander to accept a towing cable; a reciprocating hammer coupled behind the expander; a cutter coupled to a front of the expander using a ball joint, the cutter including a plurality of replaceable blades; and a floating cutter adapted to attach to the towing cable at a selectable location in a range along the towing cable and at a location separate from, and in front of the cutter.
 9. The pipe replacement device of claim 8, further including at least one replaceable blade on the cutter coupled to the front of the expander.
 10. The pipe replacement device of claim 8, further including at least one replaceable blade on the floating cutter.
 11. The pipe replacement device of claim 8, wherein the floating cutter includes a first tapered wedge.
 12. The pipe replacement device of claim 11, wherein the floating cutter includes a second tapered wedge.
 13. The pipe replacement device of claim 12, wherein the second tapered wedge is oriented opposite the first tapered wedge. 